Are the images produced by light and radio telescopes similar?

Answer 1

Usually not.

When looking at active galaxies, for example, light images will mostly reveal the stars. A radio image will mostly reveal the jets of plasma that are generated from the accretion disk around the central black hole: the jets ram into the interstellar and intergalalctic matter (dust and gas) and the braking of the charged particles generates lots of radio energy.

I've been trying to find a radio-image and an optical image of the same galaxy, but I have not found one yet.

The closest I found is at
http://en.wikipedia.org/wiki/Radio_galaxy

Look at the first image and imagine that the green portion is the visible image (it is infrared, close to visible, and shows the dust in the main disk of stars). The orange part is the radio image, showing the jets and lobes which are nowhere near the visible disk of the galaxy.

Answer 2

No they won't. Images by light telescopes will only show objects that emit or reflect visible light like stars and planets etc whereas radio telescope images would show objects that emit radio waves like pulsars, black holes etc.

Answer 3

They are similar in the degree that they are both instruments that measure electromagnetic radiation; they are different in the degree that astronomical objects radiate in many frequencies of the electromagnetic spectrum and as such the images received are bound to be different.

Answer 4

1. Heat energy. All energy is same and undifferentiated. Depending upon its level (measured in Joules) it gets categorised as heat, light etc. It is called heat energy as that is associated with heat, the aggregate kinetic energy of gas molecules in a cloud (or atmosphere). Generally heat is because of molecular processes and energy exchange therein. 2. (I told you) it is heat energy. Total heat of a system (of molecular cloud or gas) divided by the number of molecules gives the average kinetic energy per each and is measured as Temperature. Of course, the individual heat capacity of each molecule also accounts for the energy it can hold. Coming to infrared (IR), it is a part of the electromagnetic energy spectrum spanning a wavelength range of 0.1 millimetre to almost 0.7 micrometre (micron) when it meets visible part of spectrum. The nomenclature is due to the human penchant for analysis, categorisation and "naming". 3. There is in a IR telescope, 'focal plane array' (FPA) made of any of special materials depending upon the IR region we want to study (IR band is vast stretching over 8.8 Octaves). The array composed of a million or so of tiny bits of the material generates so many currents forming an array, much like the CCD array that replaced the photographic plate. All these work on the same principle of individual grains converting the energy from the photons to currents (or in case of photographic plate that was earlier used in IR also to a permanent 'hard copy'). In NIR, Cadmium Telluride is very popular. The individual currents form a planar raster of information picture elements (pict els or 'pixels' for short). Finer the graininess the more the detail one gets that an 'enlargment' reveals. The telescope is like any other optical telescope with care taken to use a glass that is transparent to IR. In FIR (Far IR) & Mid-IR it is better to suffer the attenuation of the glass medium, but it should accomplish focusing at such wavelengths. At times different materials that are transparent at IR (though appearing black to our eyes) like Germanium are shaped into lenses. 4. IR sensors (telescopes) are specially suited for studies of gas bodies like nebulae or to view through gas bodies that other wavelengths (visible & Ultra Violet) can't penetrate. This was the experience gained from the study of Venusian surface, being blocked by thick Sulfurous & CO2 clouds. Yet, atmospheric gases of Earth absorb the incoming IR light, attenuating the picture. hence it is desirable to go to high altitudes like those in Hawaiin Islands or even satellites above the atmosphere. 5. Astrophysics concerns with electromagnetic spectrum of which IR is a part, while visible region too is one. While Visible region is a sliver hardly 1 Octave wide, IR spans nearly 9 Octaves and so is a rich source of information to which we hardly opened our eyes, thanks to the advances made in modern Astronomy. IR spectroscopy is inherently ana analytical tool, much like the other (visible) spectroscopy. All the principles employed in the visible region (including the Doppler based Red and Blue shift) are applicable in IR too and have far greater promise. I wouldn't wonder if several IR bright stars get discovered in nearby areas (there might be an IR star nearer than Proxima Centauri, who knows!)that we couldn't see as they are invisible in visible region with their feeble visible energy pulling down their apparent magnitudes to 16 or 20.

Answer 5

The light signals carry greater resolution.